Heat sealing device for side seams of paper cups



May 26, 1964 o. B. LOESER 3,134,307

HEAT SEALING DEVICE FOR SIDE SEAMS OF PAPER CUPS Filed July 31, 1962 4Sheets-Sheet l "min" INVEN TOR. 00mm .8. Loesm A 110 nwevs May 26, 1964D. B. LOESER 3,134,307

HEAT SEALING DEVICE FOR SIDE SEAMS OF PAPER CUPS Filed July 31, 1962 4Sheets-Sheet 2 INVENTOR. DONALD B. LOESER Arromvsvs y 26, 1964 D. B.LOESER 3,134,307

' HEAT SEALING DEVICE FOR SIDE SEAMS OF PAPER CUPS Filed July 51, 1962 4Sheets-Sheet 5 jiy. 4.

' INVENTOR. DONALD B. LOESER BY 7 I 77 Ar-rgnm; vs

May 26, 1964 D, LOESER 3,134,307

HEAT SEALING DEVICE FOR SIDE SEAMS OF PAPER CUPS Fil ed July 51, 1962 4Sheets-Sheet 4 84 82a 85 H6 H6 48 r a9 717'!!! 52 ---77 36 |Zll"" 3 7;7/ so illil fifl 7/ 87 1 4o INVENTOR. 170mm B. LOESER Armmvsvs UnitedStates Patent 3,134,307 HEAT SEALING DEVICE FOR SIDE SEAMS OF PAPER CUPSDonald B. Loeser, Thiensville, Wis., assignor to Paper MachineryCorporation, Milwaukee, Wis., a corporation of Wisconsin Filed July 31,1962, Ser. No. 213,719 13 Claims. (Cl. 93-361) This invention relates tomachines for forming paper cups of the type using polyethylene-coatedboard, or other heat scalable material which provides the adhesive fromwhich the side seal of the cup is made. These machines usually have arotatable turret containing a plurality of mandrels upon which the cupis formed as it passes through various station locations in whichdifferent operations on the cup are performed. More particularly, theinvention relates to a heat sealing and cooling mechanism for formingthe side seal on the cup.

Prior attempts have been made to rapidly seal and cool the side seam ofa cup, for example, by circulating cooling water through a jacketsurrounding the female die. However, for one reason or another theseattempts have not proved to be satisfactory, and one of the principaldifficulties has been the inability to cool the seam either suflicientlyor promptly enough to maintain the necessary high production rates.

It has also been proposed, in the manufacture of flat bottom ortwo-piece cups, to seal the bottom by heating and then cool the same,and while these devices have proved to be somewhat satisfactory, theproblems encountered in performing such a sealing and cooling functionon the cup bottom are considerably different than those involved insealing the side seams of a cup; for one thing, the tendency for theside seal to open immediately after it has been cooled is considerablygreater due to the resiliency of the side wall and its tendency toreturn to the flat position.

In accordance with the present invention, an improved side sealing andcooling mechanism for use in the manufacture of paper cups has beenprovided and in which the heating and cooling functions are performed ina much improved and rapid manner from prior art devices, therebyresulting in extremely good production rates.

More particularly, the invention comprises a heating and cooling barunit which is alternately swingable into heating and cooling positionsdirectly on and along the side seam of the cup located on each mandrel.Thearrangement is such that the heating bar is positioned on thelongitudinal seamofthe cup for a short period of time, for example, onesecond, and is then lifted at precisely the right time and while theheat sealable material is sufficiently sticky to hold the side walls ofthe cup together. Immediately thereafter, the heating bar is swung outof the sealing position, and the cooling bar is simultaneously swunginto the position along the longitudinal seam. The cooling bar thencauses the longitudinal seam to 'cool sufiiciently to creat thenecessary holding track. The transfer of the heating bar from the 'seamand the cooling bar into the cooling position on the seam is extremelyrapid and is performed whilethe cup is being transferred from onestation to the next. to the improved method of dissipating the heat fromthe cooling bar, it is necessary for the latter to be in contact withthe longitudinal seam only a matter of a few seconds. 7

A more specific aspect ofthe invention relates to an alternatelyoperable heating and cooling bar unit of-the above type in which acooling medium, such as oil, air, or water is injected into the coolingbar, and the used medium in the bar is simultaneously thoroughly purgedDue I 3,134,307 Patented May 26, 196.4

therefrom. This purging and recharging of the cooling bar is performedat the station immediately before the side scaling function commences.This purging and recharging device comprises a pair of self-sealingnozzles located in the path of the unit and are automaticallyconnectable therewith as the unit passes this purging and rechargingstation.

These and other objects and advantages of the present invention willappear hereinafter as this disclosure progresses, reference being had tothe accompanying drawings, in which: 7

FIGURE 1 is a fragmentary, perspective view of a machine embodying thepresent invention;

FIGURE 2 is a fragmentary plan view of the machine shown in FIGURE 1,with parts being shown as broken away, removed, or in section for thesake of clarity in the drawing;

FIGURE 3 is a view taken along line 33 in FIG- URE 2, but on an enlargedscale, certain parts being shown as broken away and in section;

FIGURE 4 is a side view of the device shown in FIG- URE 3, the viewbeing taken along line 4-4 in FIG- URE 2, but on an enlarged scale, andwith certain parts shown in section;

FIGURE 5 is an elevational view taken along line 5-5 in FIGURE 2, but onan enlarged scale and with certain parts shown in section or brokenaway;

FIGURE 6 is a side view of the device shown in FIG- URE 5, the viewbeing taken along line 66 in FIG- URE 2, but on an enlarged scale, andwith certain parts shown as being broken away and in section, or removedfor clarity, and

FIGURE 7 is a view taken generally along line 77 in FIGURE 2, but on anenlarged scale.

Referring more particularly to the drawings, the machine utilizing thepresent invention comprises an eightsided rotatable turret T whichrotates about a vertical axis between a stationary table 1 and an upperstationary spider frame member 2. The turret T has eight mandrels 4extending radially therefrom, all of which are identical. These mandrelsare non-rotatable and have conventional suction passages (not shown) attheir bottom end for holding the flat bottom blank thereon. Thesemandrels also have air pressure passages (not shown) for ejecting thefinished cup from the mandrel in the conventional manner.

The mandrels are frusto-conical in shape for forming two-piece or flatbottom type of cups, but the invention is applicable also to othermachines such as those utilizing a conical mandrel for forming conicalcups.

In the illustration of the machine as shown in FIGURE 2, only sevenstations around the turret are used for the formation of cups, it beingunderstood that fewer stations would be: used for forming some types ofcups, while all eight stations may be used if other types of cups are tobe made. The turret periodically dwells for a short period of time as itrotates in the direction indicated by the arrow so that each cup beingformed pauses at each station. The seven stations used as shown inFIGURE 2 include the folding station A, first bottom curl station B,second bottom expanding station C, third bottom roller D, a transferstation E, a bottom attaching station F,

and a bottom reformerstation G.

Reciprocable tools are provided at each station in the kniwn manner tosuccessively perform various operations on the cup being formed as itrotates from one station to the next. Because many of these stations arenot concerned, per se, with the present invention, it is believedsuflicient to comment only briefly on them. For example, at station A, ablank feeding device 10 is adapted to hold a paper blank 11 in its pairof grippers 12 for passing the blank beneath the mandrel 4 located atthat station. The

blank is initially raised around the mandrel by the com plementary andsemi-cylindrical clamping members 13 and 14 which are upwardly swingablefrom the position shown in FIGURE 1 and into clamping engagement aroundthe mandrel, during which swinging movement they tightly wrap the blankaround the mandrel so as to form an overlapping sea-m along the upperside of the mandrel. The structure and function of these complementaryclamping members are fully described in the United States Patent No.2,942,530 to Bodendoerfer which issued on June 28, 1960, and entitledBlank Wrapping Mechanism for Frusto-Conical Cup Making Machines, and ifa more complete description of this station is deemed either necessaryor desirable, reference may be had to that patent.

Station B has a horizontally reciprocable tool 16 which performs thefirst curling operation on the bottom in the known manner.

Station C also has a reciprocable tool assembly 17 which expands thebottom tightly against the cup side- Wall.

Station D has another bottom roller 18 which tightly seals the jointbetween the bottom and side wall of the cup and may be of the type shownin my United States Patent No. 2,942,531, issued on June 28, 1960.

At station E, the finished cup is blown off the mandrel and into adelivery chute 19.

The bottom attaching mechanism 20 shown at station F places a partiallyformed bottom 2'31 on the end of the mandrel where it is held by suctionin the conventional manner.

Station G has a bottom reformer tool 22 (FIGURE 1) which acts on thebottom 21 to align and shape it for the wrapping of the side wall blanktherearound at the next station A, as previously mentioned.

In connection with the present invention, particular attention will bedirected to the operations at stations G, A, and B.

Cooling Medium Injection and Purging Device With the present invention,various cooling mediums, such as water, air, oil, or others may beutilized, and the term fluid will hereinafter be used in thespecification and claims to denote any such mediums.

At station G, and above and in addition to the reformer tool 22, acooling medium injection and purging device CW is reciprocally mountedin a block 23 secured to a stationary table 2301. The device is shiftedby a pair of actuating levers 24 for movement horizontally away from aheating and cooling device HC, one of which is mounted adjacent eachmandrel and toward such device for connection therewith. It is at thisstation that the cooling medium from a supply conduit 26 is injectedinto the device via the conduit 32. The used cooling medium issimultaneously purged from the device via conduit 33 and out dischargeconduit 25.

For this purpose, quick-detachable and self-sealing couplings 3t) and 31are provided, respectively, for the cold medium conduit 32 and usedmedium conduit 33, both mounted on the device CW. These couplings eachinclude a plug half 34 on the end of conduits 32 and 33, and alsoinclude a socket half 35 mounted on an end cap or distributor plate 36which is secured to the outer end of each heat seal device HC. Passages37 and 38 within the plate place the self-sealing socket halves 35 influid communication, respectively, with flexible conduits 39 and 40leading to opposite ends of a hollow cooling bar 41; more specifically,conduits 39 and 4d are in fluid communication with a cavity 42 (FIGURE6) in the bar 41.

The couplings themselves are of conventional construction and may be ofthe Hansen (l-Iill) series type, or modifications thereof. It isbelieved sufficient to say that when the device CW is reciprocatedinto'the engaging position with the heating and cooling device I-IC, the

i plug halves 34 are pushed into the socket halves 35 to form a fluidcommunication therewith. Water under pressure, compressed air, or othercooling medium is then injected under pressure into the cooling bar andthe used medium purged therefrom. Upon withdrawal of the device CW andits plugs, both the halves 34 and 35 automatically seal against leakage.

Also located at station G (see FiGURE 7) and mounted on the stationaryupper frame 2 by means of a mounting plate 44 is a loading cam 45 havinga follower contacting projection When the device I-IC rotates past thiscam, a follower 48 contacts the projection and causes rotation of thedevice BC in the direction indicated by the arrow in FIGURE 7, to theheating position.

Heating and Cooling Device The device HC is mounted on the turret forvertical movement by means of its two posts 50 which slidably extendthrough the turret (FIGURES 4 and 6) and have a block 52 rigidlyconnecting their upper ends. The lower ends of these posts are rigidlysecured by nuts 53 threaded thereon to a roller mounting bracket 54through which the posts extend. A roller 55 is rotatably mounted on thebracket and extends downwarldy therefrom so as to be able, at the propertime in the sequence of operations, to ride up on the inclined end 57(FIGURE 2) of cam track 53 to thereby hold the device HC above and awayfrom the mandrel, as will appear.

At station A the track 58 terminates as at 59 and upon leaving track 58,the roller 55 rolls onto a vertically movable button 60 secured to theupper end of rod 61.

This buttonis adapted to drop downwardly while the turret dwells andwhen the button raises back to its normal position shown by the dottedlines in FIGURE 3 when the turret indexes to the next position. Morespecifically, downward movement of the button, to the position shown inthe full lines in FIGURE 3, due to the bias of spring 62 when anotherroller 63 is moved therefrom, causes the springs 64 around posts St) topull the device HC down onto the mandrel and into firm pressing contactwith the overlapped side seal of the cup, as will more fully appear.

As the turret then rotates further, the device HC hangs on the mandrel,and the roller hangs free until it rides up on a lift trigger cam 66(FIGURES 2, 5, and 6) located on the table 1 and just past station B,for a purpose to be described. I

A horizontally positioned mounting shaft 70 extends radially outwardlyfrom the block 52 to which it is rigidly secured, as by Welding orsimilar means. It is on this shaft that the cooling bar 41 and anelectrically heated bar 71 are alternately swingable for beingpositioned directly over the side seal of the cup on the upper side ofthe mandrel.

The bars 41 and 71 are each pivotally mounted at 73 (FIGURE 6) and 74(FIGURE 3), respectively, to an enlarged portion 75 of a sleeve 76rotatable on shaft 70.

The cooling medium distribution plate 36 (FIGURE 6) is secured by capbolts 77 to the end of shaft 70 and holds the sleeve 76 captive on theshaft 70.

A locating plate 80 is welded to the sleeve 76, and it is on this platethat the follower 48 is rotatably mounted.

A trigger 82 is pivotally mounted at 83 to the upper end of the block 52and has a latch portion 84. When the device HC is in the position shownin FIGURE 3, the latch portion 84 is engageable against a shoulder 85 onthe upper side of plate 86). Thus, the trigger is biased by spring 86(FIGURE 3) to hold the device HC in the position where the hot bar isdirectly above the side seal of the cup.

The device HC remains in this position from the time it has been cockedto that position by the cam 45 at station G, until the device justpasses station B, at which time roller 55 rides up on lift cam 66.

This lifting action carries trigger 82 upwardly (FIG- URE 5) where itsone end 82a abuts against a roller 81 extending downwardly from theupper frame 2, thereby pivoting the trigger and pulling its latchportion 84 out of engagement with locating plate 80. This withdrawalpermits spring 87, connected between a pin 88 on the plate and a fixedarm 89, to rotate the device counterclockwise (FIGURE 5) to a positionagainst stop 81, and in which position the cold bar 41 is locateddirectly above and in alignment with the side seal.

The roller 55 passes quickly over the lift cam as the turret rotates,and the device HC immediately is pulled downwardly by springs 64 to pullthe cold bar 41 tightly against the overlapped seam. The pivotedmounting of bar 41 permits it to adapt itself firmly on the seam.

The cold bar continues to press against the seam, and thereby cool itsufliciently, until the roller 55 again rides up on the inclined surface57 of the main track 58.

When the cold bar is thus raised off the finished cup, the cup is blownoff the mandrel in the known manner and into the chute 19.

The hot bar is on the joint to heat it and perform the sealing actionduring the interval of arcuate travel as indicated by reference 90 inFIGURE 2. The cold bar rests on the joint during the period of arcuatetravel represented by reference 91 in FIGURE 2.

During the arcuate travel represented by numeral 92 in FIGURE 2, thecold bar is directly above the mandrel but upwardly out of contacttherewith due to the roller 55 riding on the cam track at that time.

The arcuate travel represented by numeral 93 in FIG- URE 2 is from thetime the cam 45 contacts roller 48 and cocks the device to the positionwhere the hot bar 71 is above the mandrel but raised out of contacttherewith due to the cam track, and until the device fully reachesstation A and the button 60 is lowered by roller 63 reaching a lowposition of its track 63a.

The operation of the device is such that the hot bar is in contact withthe side seal of the cup for a relatively short time, but suflicient tocause a good union.

When the hot bar is lifted from the side joint, by the action of liftcam 66, the joint is sufliciently tacky to hold the side wall togetherfor a very short time during which the device is released of trigger 82,and the cold bar is snapped into position by the spring 87.

The cold bar remains on the joint a comparatively longer time andprovides good set for the joint.

Upon reaching the station G, the fresh, cool medium is injected underpressure into the bar, thus purging from the other end of the bar theused medium which has cooled the joint and absorbed the heat from thebar.

By means of the present invention, considerably higher production rateshave been accomplished without malfunction of the machine, and aleak-proof side seam has been provided and the accuracy of the cup sizeand shape maintained uniform.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. In a paper cup making machine of the type having a mandrel aroundwhich a paper blank is wrapped to thereby produce a heat sealableside-seam, a heating and cooling device for said seam and comprising, ahot bar and a cold bar mounted adjacent said mandrel and alternatelyshiftable between a position engaging said seam and a position remotefrom said seam to thereby first heat and then cool the seam.

2. In a paper cup making machine of the type having a mandrel aroundwhich a paper blank is wrapped to thereby produce a heat sealable sideseam, a heating and cooling device for said seam and comprising anelectrically heated hot bar and a cold bar having an internal cavity andboth mounted adjacent said mandrel and each 6 alternately shiftablebetween a position engaging said seam and a position remote from saidseam to thereby first heat and then cool the seam, and a cooling fluidin jecting and purging unit mounted adjacent said device and adapted tobe in fluid communication with said cavity to thereby circulate coolingfluid therethrough.

3. In a paper cup making machine of the type having a mandrel aroundwhich a paper blank is wrapped to thereby produce a heat sealable sideseam; a heating and cooling device for said seam and comprising, a frameshiftably mounted adjacent said mandrel for moving said device intocontact with and away from said seam, a hot bar and a cold bar swingablymounted on said frame for alignment with said seam and alternatelyengageable with said seam to thereby first heat and then cool the seam,and a cooling fluid injecting and purging unit mounted adjacent saiddevice and adapted to be in fluid communi cation with said cavity tothereby circulate cooling fluid therethrough.

4. In a paper cup making machine of the type having a mandrel aroundwhich a paper blank is wrapped to thereby produce a heat sealable sideseam, a heating and cooling device for said seam and comprising, a frameshiftably mounted adjacent said mandrel for moving said device intocontact with and away from said seam, an electrically heated hot bar anda cold bar having an internal cavity and both bars being swingablymounted on said frame. for alignment with said seam and alternatelyengageable with said seam to thereby first heat and then cool the seam.

5. In a paper cup making machine of the type having a mandrel aroundwhich a paper blank is wrapped to thereby produce a heat sealable sideseam; a heating and cooling device for said seam and comprising, a framereciprocably mounted adjacent said mandrel for moving said device intocontact with and away from said seam, a hot bar and a cold war swingablymounted on said frame for alignment with said seam and alternately en-,gageable with said seam to thereby first heat and then cool the seam,and means for reciprocating said device toward and away from said scamin timed relationship with said swinging movement of said bars.

6. In a paper cup making machine of the type having a mandrel aroundwhich a paper blank is wrapped to thereby produce a heat sealable sideseam; a heating and cooling device for said seam and comprising, a framere ciprocably mounted adjacent said mandrel for moving said device intocontact with and away from said seam, a hot bar and a cold bar swingablymounted on said frame for alignment with said seam and alternatelyengageable with said seam to thereby first heat and then cool the seam,means for reciprocating said device toward and away from said seam intimed relationship with said swinging movement of said bars, and acooling fluid injecting and purging unit mounted adjacent said deviceand adapted to be in fluid communication with said cavity to therebycirculate cooling fluid therethrough.

7. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is wrappable to form a side seam located alongone side of each of the mandrels, seam heating and cooling devicesmounted on said turret and one adjacent each of said mandrels, saiddevices each comprising, a hot bar and a cold bar mounted for alternateshifting into contact with and away from the side seam on its respectivemandrel to thereby first heat and then cool said seam.

8. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is wrappable to form a side seam located alongone side of each of the mandrels, seam heating and cooling devicesmounted on said turret for rotation therewith and one adjacent each ofsaid mandrel-s, said devices each comprising, a hot bar and a cold barmounted for alternate shifting into contact with and away from the sideseam on its respective mandrel to thereby first heat and then cool saidseam, said cold bar having a cooling fluid cavity therein, means locatedadjacent the path of rotation of said devices and successivelyengageable therewith for injecting fresh cooling fluid into said cavityand simultaneously purging used fluid therefrom.

9. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is Wrappable to form a side seam located alongone side of each of the mandrels, seam heating and cooling devicesmounted on said turret and one adjacent each of said mandrels, saiddevices each comprising, a hot bar and a cold bar mounted for alternateswinging into alignmentwith the side seam on its respective mandrel, andmeans for reciprocating said devices toward and away from theirrespective mandrel to thereby bodily shift the aligned bars intoengagement with said seam and consequently heat and then cool said seam.

10. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is wrappable to form a side seam located alongone side of each of the mandrels, seam heating and cooling devicesmounted on said turret and one adjacent each of said mandrels, saiddevices each comprising, a hot bar and a cold bar mounted for alternateswinging into alignment with the side seam on its respective mandrel,said cold bar having a cooling fluid cavity therein, means locatedadjacent the path of rotation of said devices and successivelyengageable therewith for injecting fresh cooling fluid into said cavityand simultaneously purging used fluid therefrom, and means forreciprocating said devices toward and away from their respective mandrelto thereby bodily shift the aligned bars into engagement with said seamand consequently heat and then cool said seam.

11. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is wrappable to form a side seam located alongone side of each of the mandrels, frames shiftably mounted on saidturret and one adjacent each of said mandrels, a hot bar and a cold barmounted on said frame for alternate shifting into and out of alignmentwith the side seam on its respective mandrel, and means to shift saidframes in timed relationship with rotation of said turret to therebymove the aligned bars into contact with said seam to thereby first heatand then cool said seam.

12. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is wrappable to form a side seam located alongone side of each of the mandrels, frames reciprocably mounted on saidturret for rotation therewith and one frame adjacent each of saidmandrels, a hot bar and a cold bar mounted on each frame for alternateshifting into and out of alignment with the side seam on its respectivemandrel, said cold bar having a icooling fluid cavity therein, meanslocated adjacent the path of rotation of said frames and successivelyengageable with each of said frames for injecting fresh cooling fluidinto its cold bar cavity and simultaneously purging used fluid from saidcavity, and means to reciprocate said frames in timed relationship withrotation of said turret to thereby move the aligned bars into contactwith said seam to thereby first heat and then cool said seam.

13. In a paper cup making machine of the type having a rotatable turretincluding a plurality of circumferentially spaced mandrels around eachof which a paper blank is wrappable to form a side seam located alongone side of each of the mandrels, frames reciprocably mounted on saidturret for rotation therewith and one frame adjacent each of saidmandrels, a hot bar and a cold bar mounted on eachvframe for alternateshifting into and out of alignment with the side seam on its respectivemandrel, each cold bar having a cooling fluid cavity therein, flexibleconduits between each frame and its cold bar cavity, fluid supply meanslocated adjacent the path of rotation of said frames and successivelyengageable with each of said frames for injecting fresh cooling fluidinto its cold bar cavity via said conduits and simultaneously purgingused fluid from said cavity, said fluid supply means includingquick-detachable and self-sealing couplings, and means to reciprocatesaid frames in timed relationship with rotation of said turret tothereby move the aligned bars into contact with said seam to therebyfirst heat and then cool said seam.

References Cited in the file of this patent UNITED STATES PATENTS2,326,931 Dalton et a1 Aug. 17, 1943 3,049,979 Sayford Aug. 21, 19623,050,916 Gausman et a1 Aug. 28, 1962

1. IN A PAPER CUP MAKING MACHINE OF THE TYPE HAVING A MANDREL AROUNDWHICH A PAPER BLANK IS WRAPPED TO THEREBY PRODUCE A HEAT SEALABLE SIDESEAM, A HEATING AND COOLING DEVICE FOR SAID SEAM AND COMPRISING, A HOTBAR AND A COLD BAR MOUNTED ADJACENT SAID MANDREL AND ALTERNATELYSHIFTABLE BETWEEN A POSITION ENGAGING SAID SEAM AND A POSITION REMOTEFROM SAID SEAM TO THEREBY FIRST HEAT AND THEN COOL THE SEAM.